question_answer

The image formed by a spherical mirror is real, inverted and is of magnification -2. If the image is at a distance of 30 cm from the mirror, where is the object placed? Find the focal length of the mirror. List two characteristics of the image formed if the object is moved 10 cm towards the mirror.

Answer:

Given: \[m=-2,\,v=-30\,cm\]

We know that, \[m=\frac{-v}{u}\]

\[-2=\frac{30}{u}\]

\[u=-15cm\]

Now, \[f=\frac{uv}{u+v}=\frac{-15\,\times -30}{-15-30}=\frac{450}{-45}=-10cm\]

If the object is shifted 10 cm towards the mirror then, \[u=-5\,cm,\] i.e., object is between pole and focus, thus image formed will be virtual, erect and magnified.